Why does Apple still reserve @me.com and @mac.com addresses for people who obtained them during the older .Mac and MobileMe eras? Apple's current service uses iCloud branding, but some of the underlying mail infrastructure and routing still appears connected to the older domains. Since many short and memorable @icloud.com addresses are already taken, reopening the legacy domains could give users more usable choices and make better use of established Apple brands. Is the restriction mainly technical, or is it simply a branding and account-management decision?
2 Answers
The fact that Apple’s systems can route or process mail for the older domains doesn’t necessarily mean they have a whole new pool of addresses ready to issue. There would also be account-recovery, impersonation, trademark, migration, and duplicate-name problems to manage. Apple may eventually change its policy, but there isn’t an obvious technical requirement forcing it to reopen those domains. They’re valuable precisely because they’re limited and associated with earlier services.
It’s mostly a branding and product-history decision. @mac.com belonged to the .Mac service, @me.com came with MobileMe, and @icloud.com is associated with the current iCloud service. Even if the mail systems share infrastructure, that doesn’t mean Apple wants to present all three domains as interchangeable. Keeping the older domains tied to existing accounts also avoids disrupting the identity and expectations of longtime customers.

That makes sense, although it still feels like a missed opportunity when many of the clean current addresses are already unavailable. Reusing the older domains with careful safeguards could give people more options without affecting existing owners.